(293b) Inhibition of Foreign Body Capsule Formation By Implanted Zwitterionic Hydrogels

Materials or devices implanted in the body play an important role in drug delivery, in vivo sensing, artificial prostheses, and tissue engineering. However, these implants are encapsulated by a dense collagen capsule, produced by the body’s defense system, about three weeks after implantation. The capsule forms on all implants and is permeation barrier to most molecules important for detection and delivery. For example, implanted biosensors or cell-based constructs require efficient mass transport with the environment, but fail due to the low vascularity and impermeable capsule. In addition, the capsule causes undesirable complications to artificial prostheses and cosmetic implants, such as distortion and pain. The collagenous capsule formation is one consequence of the foreign body reaction, which is used by mammals as a natural protective mechanism. In this work, we demonstrate that ultra-low fouling zwitterionic hydrogels can resist the formation of a capsule for at least 3 months after subcutaneous implantation in mice. Moreover, zwitterionic hydrogels can also promote angiogenesis in their surrounding tissue, which is also beneficial to the mass transport of molecules between the body and the implants. Findings in this work open new opportunities for the development of biocompatible and high-performance implantable medical devices.